The Ti?15 is a 14.4-volt brushless impact driver that is also a drill/driver. The design is based on the idea that tradesmen should be able to use a single tool for most drilling and driving applications.

Like most of Festool’s drill/drivers, the Ti?15 has a 1/4-inch drive socket that various heads can be connected to. The tool includes a 1/2-inch chuck for non-impact drilling and driving, and an adapter that accepts such optional attachments as a right-angle drive, an offset drive, and a drywall screwdriver head. (These heads are not designed for impact use, and the adapter disables the tool’s impact mechanism.)

I’ve had one of these tools since last summer and tested it when I tested impact drivers for a previous review (“18-Volt Brushless Impact Drivers,” winter 2013). I didn’t include it in that story because it’s a 14.4-volt model and different enough to deserve separate coverage.

DRIVING PERFORMANCE

According to Festool, the Ti?15 is limited to 885 inch-pounds of torque, which is well below the claimed output of the 18-volt impact drivers I tested.

As part of that testing I drove 1/4-inch by 3 1/2-inch Simpson SDS lags into a thick Parallam beam — a stern test for any impact driver. The Ti?15 drove the first 18 lags in an average of 8.8 seconds, and its battery was depleted after driving 49. This would put it near the bottom of the pack in that test. However, what the test did show was that this tool — though not designed for heavy-duty work — can drive sizeable lags by the handful when necessary. In real-world applications, the Ti?15 did a good job driving up to 4-inch driver screws without a pilot hole in construction lumber.

The Ti?15 is equipped with a speed-control dial for its drilling mode, but because the tool requires all the power it can muster, it should be left at the maximum setting. For lighter work, the user can dial down the speed or feather the trigger to keep from overdriving. Fortunately, the trigger is quite sensitive.

DRILLING PERFORMANCE

Drilling small pilot holes in wood presented no challenge, but since the Ti?15’s manual specified a maximum hole size (in wood) of only 1/2 inch, I wanted to see if it was really that light-duty of a drill. The tool had no trouble driving a self-feeding auger bit of up to 5/8 inch diameter through dry 2-by material, but a 3/4-inch bit stopped it cold every time. I’d begin to drill, and the electronic circuitry would cut power to the motor when the torque load exceeded the tool’s maximum limit. It never slowed or struggled — it simply stopped.

I was able to complete 1-inch holes with a nonfeeding spade bit, but the tool stalled at least once per hole. By way of comparison, my battered old 14.4-volt drill/driver powers right through — even in high gear.

The electronic clutch action of the 16 speed settings stops the tool motor at a preset torque for each setting, but doesn’t make much of a difference in driving depth. I found it easiest to leave the dial set to high and use the trigger alone.

Unlike standard drill/drivers, this model has a single gear setting; it lacks a low gear for drilling bigger holes. For a tool of its size, it’s not particularly capable in drill mode.

Features

This tool’s basic features are excellent. The rubberized grip surfaces, onboard fuel gauge, removable two-sided belt hook, and LED headlight are in line with the amenities found on other premium drills and impact drivers. The Ti?15 comes in a Systainer, a modular case that is superior to the cases most tools are supplied with.

Centrotec bit holder. Operating the tool in impact mode requires the use of the included Centrotec impact bit holder. Like standard Centrotec holders (which have thinner walls), this one takes proprietary Festool bits.

Most contractors don’t have a supply of Festool bits (nor do most contractor supply stores), so they have to use the included Centrotec-to-1/4-inch magnetic bit adapter. Only 1-inch-long bits are recommended for use in the adapter. This is a basic shortcoming; many people (myself included) don’t like using magnetic bit holders, especially for impact driving, because the long adapter flexes and absorbs a lot of the impact energy.

Drill chuck. Impact drivers lack the transmission and built-in motor brake of drill/drivers, so you cannot tighten the chuck of the Ti?15 in the usual way. You must run the motor or use two hands on the chuck to make the jaws close in on the bit. To get it tight, you must push the chuck into the motor housing until it engages with a locking gear that allows you to crank it down. This works, but is so different from normal it’s hard to get used to.

THE BOTTOM LINE

Like most combination tools, the Festool Ti?15 represents a compromise. To give it multiple functions, the manufacturer made sacrifices in both performance modes and also made it larger and heavier than single-function tools in its voltage class. Still, buying the Ti?15 may be a better deal than getting two separate tools — especially newer brushless-motor models.

This tool does not have the power needed for general carpentry, and the advantage of using it as both a drill and an impact driver will be lost on tradesmen who prefer to use the optimal tool for each operation. It would be more suitable for trim carpenters, cabinetmakers, and cabinet installers — tradesmen who may benefit from the versatility offered by multiple heads and who perform medium-duty drilling and driving tasks.

Michael Springer is the former executive editor of Tools of the Trade.